Expression of Aflatoxin Genes Nor-1, Omt-B, Omt-A, and Ord-A to Differentiate between Aflatoxinogenic and Non-Aflatoxinogenic Strains of Aspergillus Flavus and Aspergillus Parasiticus

Accepted 4th January, 2016

Abstract

Eleven strains of Aspergillus flavus and Aspergillus parasiticus, were isolated from Egyptian soil and air. The isolated strains have been screened for their ability to produce aflatoxins (B1, B2, G1 and G2) in three types of media (Czapek's Dox, potato dextrose and glucose peptone yeast). Differentiation between aflatoxinogenic and non-aflatoxinogenic strains was carried out using TLC to detect B1, B2, G1 and G2. The three types of broth media differed in their potentiality to enhance aflatoxins production by the selected strains. Type of produced toxins differed according to the constituent of media and fungal species, as well as its strains. The expression of four aflatoxin biosynthetic pathway genes Nor-1 (Afl-D), Omt-B (Afl-O), Omt-A (Afl-P), and Ord-A (Afl-Q) was evaluated in the eleven strains using RT-PCR. Mostly the results of the conventional method were concomitant with that of RT-PCR. omt- B, omt- A and ord- A are important in differentiation between aflatoxigenic and nonaflatoxigenic strains.